A semiconductor device is generally prepared by the following processes:
i) dicing a large-diameter silicon wafer with a circuit pattern formed thereon in silicone chips,
ii) thermocompression bonding the chip on a lead flame via a curable liquid adhesive, i.e., die bonding adhesive, to fix the chip,
iii) wire bonding the electrodes of the chip to pads, and
iv) encapsulating the chip for protecting the chip from the environment and handling facility.
The encapsulating is generally performed by resin transfer molding because of good productivity and low costs.
As miniaturization and multifunctionalization of electric and electronic appliances advances, an area array type package without a lead frame, for example, Chip Size Package (CSP), and stack type packages such as stacked CSP and System in Package (SiP) are more and more used. These packages are required to have higher resistance to thermal shock than those of conventional packages.
In addition, a reflow temperature for lead-free solder is as high as 265° C., requiring higher heat resistance. Among package constituents, a die bonding agent is relatively easy to be modified compared with other constituents, so that the modification of the die bonding agent aiming to lower thermal expansion coefficient, higher adhesion strength, and higher resistance to thermal shock is desired.
A composition comprising a polyimidesilicone resin is known to have excellent properties such as heat resistance from Japanese Patent Application Laid-Open No. 2006-5159. The silicone moiety of the composition contributes to the improved resistance to thermal shock. However, there still is room for improvement in some properties such as thermal expansion coefficient.
Another adhesive composition comprising a silicone moiety is an alkoxy-modified epoxy resin known from Japanese Patent Application Laid-Open No. 2006-111701. The resin is used for adhering a flexible circuit board.